(1) Field of the Invention
The present invention relates to a combustion system for an engine, such as a gas turbine engine, and more particularly, to a compliant metal support for a ceramic combustor liner used in the combustion system.
(2) Prior Art
A gas turbine engine consists of an inlet, a compressor, a combustor, a turbine, and an exhaust. The compressor draws in ambient air and increases its temperature and pressure. Fuel is added to the compressed air in the combustor to further raise gas temperature. The high temperature gas expands in the turbine to extract work that drives the compressor and other mechanical devices such as an electric generator.
To reduce NOx produced in the combustor, it is desirable to reduce flame temperature. This requires a high percentage of the compressed air to be mixed with the fuel to produce a lean fuel air mixture. Such a lean combustion reduces the air available for combustor liner cooling and/or increases pressure loss during the cooling of the combustor liner. To lower the cooling air requirement and the attendant pressure loss, high temperature ceramic materials have been proposed for combustor liners. Although ceramic materials have excellent high temperature strength, their coefficients of thermal expansion (CTE) are much lower than those of metals. Thermal stress arising from the mismatch of the CTEs poses a challenge to the insertion of ceramic combustor liner into gas turbine engines.